BOARD01350

• Board Meeting Date: 1/24/2006
• Description: WSP Section - Colorado River Issues - Development of Opearations for Lakes Powell and Mead under Low Reservoir Conditions, including the Development of Lower Basin Shortage Criteria
• Board Meetings - Doc Type: Memo

4-". . '.'

Agenda Item 24
January 24-25, 2006 Board Meeting
Page 2 of3

possibility oftamarisk removal, and "Water Supply Augmentation Programs" such as
precipitation management and desalination.
The purpose of this memorandum is to update the Board on the progress of
discussions to date, which have been focused mainly on coordinated management of
Lakes Powell and Mead under low reservoir conditions. Attached are two diagrams of
the various operational strategies that have been analyzed by the ''Technical
Committee" and presented to representatives of the 7-basin states. Also attached are a
basin map and reservoir teacup diagrams showing critical reservoir elevations and
volumes, which will be discussed with Board Members during the January meeting.
The instruction to Reclamation is to complete the development of coordinated
management strategies for the operations of Lakes Powell and Mead under low
reservoir conditions and the development of Lower Basin Shortage Guidelines by
December 2007. If this time line is to be adhered too, the 7 -basin states will need to
develop the coordinated management strategy by the first week in February in order
for Reclamation to complete the development of alternatives so that the DEIS will be
available in December 2006 and the FEIS in October 2007.

.

Technical Workgroup Evaluations
The 7-Basin State representatives established a Technical Workgroup to
analyze different options for the conduct of coordinated operations between Lakes
Powell and Mead under low reservoir conditions. The Technical Workgroup has
reduced the many possibilities to those shown on the attached tables. The Technical
Workgroup will continue to analyze different target elevations in order to meet the
stated goals of (1) minimizing the extent and duration of Lower Basin shortages and
(2) maximizing the protection afforded to the Upper Basin by Lake Powell against
possible calls upon the Upper Basin to curtail uses in order to meet the delivery
requirement to the Lower Basin of 75 MAF over any 10- year period plus one-half of
any deficiencies in deliveries of 1.5 MAF annually to Mexico. Further refinements to
these suggested operations will be presented to the 7-Basin State representatives on
January 30-31,2006.
I have attached some selected graphs showing the results of some of the latest
model runs that Reclamation has made for the Technical Workgroup and which I
believe best illustrate the Workgroups findings to this point in time. In short, the
Upper Basin Workgroup members prefer "Hybrid rev2 for Powell operations in
coordination with step shortages at Lake Mead under the "Step Shortage rev 1 " option.
This scenario provides improved protection for the minimum power pool at Lake
Powell over current operations and significant benefits to the Lower Basin. The
Lower Basin prefers "Hybrid rev 1 - Step Shortage rev1." While the Lower Basin
preference comes closer to maximizing benefits for the Lower Basin it comes at the
considerable expense of Lake Powell storage in slightly below average to slightly
better than average years.
It should be noted that either scenario is preferable to the current operations
which result in Lake Powell drawing down early going into a drought, while Lake
Mead is sheltered from any drought impacts until Lake Powell releases are reduced to
8.23 MAF. Once Powell releases are at 8.23 MAF, Lake Mead losses approximately
1.3 MAF annually until Lake Powell returns to the 602(a) storage level, above which

.~

.